1. Field of the Invention
The present invention relates to a rotary scanner and a light beam scanning system, and more specifically to a rotary scanner for scanning a light beam emitted from a light source on a light receiving surface and a light beam scanning system with such a rotary scanner.
2. Description of Related Art
A light beam scanning system provided with a polygonal mirror has been developed into various types to be used as an image writing device and an image reading device. The polygonal mirror is driven to rotate by a motor at a constant speed. If the motor cannot keep the constant speed, accurate image formation will be impossible. Incidentally, motors are classified into brush motors and brushless motors, and a brushless motor is used to drive the polygonal mirror. Brushless motors are good in the accuracy of rotation but expensive. Brush motors are inexpensive. However, since brush motors are inferior in the accuracy of rotation, they have not been used for driving a polygonal mirror.